SrCeO3 as a novel thermal barrier coating candidate for high-temperature applications

In this study, perovskite-type SrCeO3 was proposed and investigated as a novel thermal barrier coating (TBC) material for applications above 1200 °C. Results indicated that SrCeO3 has a low thermal conductivity, decreasing from 2.84 W/(m⋅K) to 1.74 W/(m⋅K) with increasing temperatures from room temperature to 800 °C. The thermal expansion coefficients are in a range of 9.67 × 10−6 K−1-10.6 × 10−6 K−1, which are comparable to those of the traditional yttria stabilized zirconia (YSZ). The results of thermogravimetric-differential scanning calorimeter (TG-DSC) analyses and long-term annealing tests indicated that SrCeO3 has excellent phase stability from room temperature to 1300 °C. The above merits suggested that SrCeO3 has a good potential for TBC applications at temperatures higher than 1200 °C. Therefore, plasma sprayed SrCeO3 coating was further produced and characterized. However, coated samples failed very early during thermal cycling. The low fracture toughness (1.09 MPa m1/2), high sintering activity and coating composition deviation are deemed to be the major factors which lead to the early spallation of SrCeO3 coating. Finally, methods for the improvement of the thermal shock life of SrCeO3 TBC were proposed.